Shield with continuously concave inner sidewall

1. An apparatus comprising: a main pole having first and second sidewalls with wall angle θ 1 with respect to a down-track direction; and a shield at least partially surrounding the main pole, the shield having a continuously concave inner sidewall spaced from the main pole and having a wall angle θ 2 greater than angle θ 1 .

2. The apparatus of claim 1 , wherein the main pole and shield are separated by an insulating material.

3. The apparatus of claim 1 , wherein the inner sidewall of the shield has a shape that resembles a wine glass.

4. The apparatus of claim 1 , wherein the inner sidewall of the shield is longer than the sidewalls of the main pole such that the inner sidewall extends past the sidewalls of the main pole.

5. The apparatus of claim 1 , wherein the inner sidewall of the trailing shield defines a throat region proximal a leading edge of the main pole.

6. The apparatus of claim 5 , wherein the throat region of the shield further comprises throat and mouth that are each continuously concave.

7. The apparatus of claim 1 , wherein the shield completely surrounds the main pole at an air bearing surface.

8. The apparatus of claim 1 , wherein the main pole material is CoFe or NiFe or alloys thereof.

9. The apparatus of claim 1 , wherein the shield material is CoFe or NiFe or alloys thereof.

10. A write head comprising: a main pole with an air bearing surface (ABS), the main pole having a leading edge, a trailing edge, and a first sidewall with wall angle θ 1 ; and a shield having a continuously concave first inner sidewall that substantially surrounds the main pole with a wall angle θ 2 greater than θ 1 , the first inner sidewall separated from the trailing edge of the main pole by a first distance and separated from the leading edge of the main pole by a second distance, smaller than the first distance, the second distance defining a throat region.

11. The write head of claim 10 , wherein the main pole and trailing are separated by an insulating material.

12. The write head of claim 10 , wherein the first inner sidewall of the trailing shield is longer than the at least one sidewall of the main pole.

13. The write head of claim 10 , wherein the first inner sidewall of the trailing shield extends away from the main pole towards a return pole to define a mouth region.

14. The write head of claim 13 , wherein the mouth region is separated from the main pole by a third distance, less than the first distance and greater than the second distance.

15. The write head of claim 10 , wherein the shield has a second inner sidewall having the wall angle θ 1 and positioned to face an opposite side of the main pole.

16. The write head of claim 10 , wherein the main pole material is CoFe or NiFe or alloys thereof.

17. The write head of claim 10 , wherein the shield material is CoFe or NiFe or alloys thereof.

18. A method of recording magnetic data comprising: writing to a medium with a main pole with first and second sidewalls with wall angle θ 1 with respect to a down-track direction; shielding the main pole with a shield at least partially surrounds the main pole with a continuously concave inner sidewall spaced from the main pole and having a wall angle θ 2 greater than angle θ 1 .

19. The method of claim 18 , wherein the inner sidewall of the shield approaches the main pole towards a leading edge of the main pole.

20. The method of claim 18 , wherein the shield defines a gap that has a uniform distance between the main pole and a trailing edge of the shield.